High voltage transformer



June 20 1933. A MEYERHANS 1,914,751"

HIGH VOLTAGE TRANSFORMER Filed Nov. 9, 1931 2 Sheets-Sheet 1 June 20, 1933. A MEY 1,914,751

man vomms TRANSFORMER Filed Nov. 9, 1931 2 Sheets-Sheet 2 Patented June 20, 1933 UNITED STATES 7 AUGUST MEYERHANS, OF B ADEN, SWITZERLAND HIGH VOLTAGE Application filed November 9, 1931, Serial No.

This invention relates to improvements in electric transformers and more particularly to transformer structures in which at least a portion of the tank retaining the electrically operative portions of the transformer is made of insulating material.

It has been found that the large and expensive insulating bushings for high voltage transformers may be eliminated if at least a portion of the tank structure retaining the electrically operative portions of the transformer is made of insulating material. With such tank the high voltage terminals may be taken through or may be attached directly to metallic portions of the tank which are separated from each other by the insulating por-' tion of such tank. In such transformers the mid-point of the high voltage or primary winding is usually connected with the core.

2 When the transformer tank ishowever constructed with conductive bottom and top portions separated from each other only by a single insulating tank portion it is necessary that the windings be insulated from each 555 other and from the core for one-halfthe voltage of the line relative to ground. The core must also be insulated from the bottom portion of the tank for one-half the voltage which requires special insulating means to 39 support the core. I

It is, therefore, among the objects of the present invention to provide an electric trans former structure of the character above described in which the core need not be supported on a special insulating frame within the tank.

Another object of the invention is to provide a transformer structure such as above indicated in which the core is supported directly upon the tank structure at one-half the voltage relative to ground.

Another object of the invention is to provi do an electric transformer structure in which a portion of the tank retaining the electrically operative portions of the transformer is formed of insulating material and in which the core is supported upon a frame which is secured to a portion of the transformer tank at one-half the voltage above ground.

TRANSFORMER 5 73,815,'and in Germany November 11, 1930.

Objects and advantages other than those above set forth will be apparent from the following description when read in connection with the accompanying drawing, in which;

Fig. 1 is a sectional elevation through a transformer embodying the present invention; and

Fig. 2 isa sectional View taken along lines II--II of Fig. 1.

The tank structure which is adapted to contain' the electricallyoperative portions of a transformer is made up of a conductive bottom portion 1 on which is supported a coaxial cylinder portion 2 of insulating material. A short conductive material portion 3 oins the cylinder portion-2 with a second coaxial cylinder portion of insulating material 4 on which is supported a top portion 5 which closes the tank. The insulating cyllnders 2 and 4 are preferably provided with outwardly and downwardly extending skirts as is usual in the construction of insulators for use out of doors. All of the joints such as between the bottom 1 and lower cylinder 2, lower cylinder 2 and middle portion 3, middle portion 3 and upper cylinder 4, and between the upper cylinder 4 and the top 5 are made by means of flanges and rings as is usual when joining metallic structures or When joining, insulating material structures to metallic structures and are suitably sealed in fluid-tight relation if the tank is to be filled with an insulating liquid or a gaseous insulation.

The electrically operative portions of the transformer comprise a core 7 and a plurality of windings on each core leg including a high voltage or primary winding which is divided into several portions 8a, 8b, a low voltage or secondary winding 9 and an equalizing winding divided into several portions 10a, 10b and 100. The core 7 is preferably supported by means of rods 11 which extend through holes in the core and which are carried by metal supporting members 12 extending across the tank and secured at the ends thereof to the conductive middle portion 3 by bolts extending through flanged portions of the members 12 and portion 3,

as shown in the drawings, or by other suitable means. The primary windings 8a and SK) are arranged about the leg of the core on either side of the cross supports 12 and are conductively connected at the mid-point with the core and with the supporting members 12. To prevent the flow of flux from the core and supporting rods through the cross supporting members by reason of the fluX linking therethrough it is desirable that the conncctions therebetween be provided with insulation as at 13. It will be seen that the insulating portions of the tank extend beyond the ends of the high voltage winding for the purpose of securing the proper potential distribution thereover. One terminal of the high voltage winding is taken through or is attached to the bottom 1 as at 16 while the other terminal is similarly taken through or attached to the top 5 as at 17 thereby avoiding the use of large and expensive in sulating bushings for such terminals, sufficient insulation being obtained between the two terminals of the high voltage winding by the insulating portion of the tank struc ture itself. The low voltage winding 9 is arranged about the legs of the core 7 adjacent the lower yoke thereof and the terminals of such winding are taken out through the bottom 1 as at 18 and 19 preferably by the use of insulating bushings. The equalizing windings 10aand 10?) are arranged about the core concentrically and opposite the high voltage windings 8a and 8b and the equalizing winding section 100 is arranged opposite and concentricallly with the low voltage winding 9.

In addition therefore to elimination of the large and expensive high voltage bushings heretofore required for the terminals of electric transformers the present invention provides a greatly simplified internal construction in that the necessity for special supporting means for the core of such character as to be capable of insulating the core for one-half the voltage from ground is now avoided. The use of cross supports by which the core is directly supported upon the tank has the great advantage that large transformers of the character described may be constructed withoutditiiculty and that the manufacture particularly of the insulating cylinder portions of the tank is materially simplified while the assembly of the entire transformer is facilitated and the transformers structure as a whole is less expensive.

Although but one embodiment of the present invention has been illustrated and described it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

The invention claimed is:

l. A transformer comprising a metal bottom port-ion at ground potential, a side wall portion of insulation mounted on said bottom port-ion, a. metal cover mounted on said side wall portion and subject to high potentials, a metal supporting member carried by said side wall intermediate the ends thereof, a transformer core supported by said supporting member, a high potential winding on said core and having leads connected to said bottom portion and said cover respectively and having an intermediate tap connected to said supporting member and said core, and a low potential winding on said core and having leads extending through said bottom portion.

2. In combination, a transformer casing comprising a metal bottom at ground potential, a cover member and insulating side walls therebetween, atransformer core supported from said side walls, a high potential winding on said core and having leads extending through said bottom and cover member respectively. and means for electrically connecting said core to a mid-portion of said winding so as to reduce the maximum potential between said winding and said core.

3. In combination, a transformer casing comprising a metal bottom at ground potential, a cover member and insulating side walls therebetween. a transformer core sup ported from said side walls. a high potential winding on said core and having leads extending through said bottom and cover member respectively, and means for electrically connecting said core to a mid-portion of said winding so as to maintain said core at a midpotential with respect to said bottom and cover members.

4. In a transformer structure, a tank element comprising a conductive top portion, a conductive bottom portion, a conductive intermediate portion, and wall portions of insulating material severally joining said top portion with said intermediate portion and said bottom portion with said intermediate portion to form a closed casing, a plurality of conductive supporting members afiixed to said intermediate portion and extending across the interior of said casing, core members supported on said members intermediate said top and bottom portions, windings arranged on said core, and means insulating said core members against flow of flux therefrom to said supporting members.

5. A transformer comprising a metal bottom portion at ground potential, a side wall portion of insulation mounted on said bottom portion, a metal cover mounted on said side wall portion and subject to high potentials, a metal supporting member carried by said side wall intermediate the ends thereof, a transformer core supported by said supporting member, and a high potential Winding on said core and having leads connected to said bottom portion and said cover respectively and having an intermediate ta connected to said supporting member an said core.

In testimony whereof I have hereunto subscribed my name this 26th day of October AUGUST MEYERHANS. 

